Focusing issues

[cygnusx1]

I'm having endless hassles trying to get either my Meade DSI or Logitech webcam to focus with my Scopos 66mm APO when using PHD.

One thing that annoys me greatly with the Scopos 66mm is that when the focuser is even partially extended, there is play in the extension tube, making keeping tight focusing harder and introducing wobble.Surely it should be rigid?? Not sure if the WO 66 has the same issue?

I have tried focusing with both 2x and 3x barlows (need to for autoguiding), but seem to take ages to find the sweet spot - i have to use the focuser, adjust the barlow or even move the nosepiece of the Meade/Webcam in and out.

Is there any way to make this procedure easier and quicker, as i spend ages trying to focus and then losing focus if even slight adjustments are made along the image train.

I need a solution to this, it's driving me batty!

[Andrew*]

tried a hartmann mask?

[daz]

Parfocal rings and an old EP?

[Stardust]

Just had a look at my ZS66 sd and it's solid, no movement even at full extension.

Dave